The invention relates to a locking device for three-position ball valves, e.g. of the type for use in testing and draining fire suppression water sprinkler systems.
Fire suppression systems typically consist of a multiplicity of sprinklers disposed about a building or a region of a building. The sprinklers are connected to an arrangement of piping extending from a source of water under pressure. In the usual system, the sprinklers are closed by a fusible link or bulb engineered to release in the presence of a predetermined temperature to allow water to flow from the sprinkler to suppress a fire. Typically, the piping arrangement terminates at a test valve, and means are provided, usually at an initial point in fire suppression piping where it is connected to the external source of water, to detect flow of water into the system, indicating that at least one sprinkler has been actuated, e.g. by the presence of a fire, and also to trigger an external alarm, e.g. by actuation of a water motor or the like.
For insurance purposes, each fire suppression system must be tested periodically, both to ensure that the piping system is under pressure and that the external alarm is operational. For the purpose of repair, it is also, at times, necessary to drain the piping system.
It has been suggested, e.g. as described in McHugh U.S. Pat. No. 4,741,361, the disclosure of which is incorporated herein by reference, to include both functions in a single three-position ball valve disposed at the piping system termination. The ball valve in a first (off) position secures the piping system under pressure. A second (drain) position allows a limited, predetermined flow of water through the valve to simulate actuation of a single sprinkler head, in order to test the function of the external alarm. In a third (drain) position, the valve is more fully opened to allow the piping system to drain (after the external source is shut-off), e.g. for repair to the system.